Nadal, the top seed, of course, in Sao Paulo, was a shocking loser at the hands of Argentine Horacio Zeballos in last week's final in Vina Del Mar, Chile. It marked his first action in seven months after being sidelined with a knee injury.

Zeballos will not capture his second ATP World Tour title this week, as he succumbed to Chilean qualifier Paul Capdeville, 6-7 (5-7), 6-0, 3-0, retired, in Sao Paulo on Wednesday.

This week's second seed is two-time reigning champion Nicolas Almagro, who beat Italian Filippo Volandri in last year's finale here and also captured this event in Costa do Sauipe in 2008 and 2011.